N-Fluoroalkylpyrazolyl-substituted Nitronyl Nitroxides

N-Fluoroalkylpyrazolyl-substituted Nitronyl Nitroxides Full article

Journal

Journal of Molecular Structure
ISSN: 0022-2860 , E-ISSN: 1872-8014

Output data

Year: 2022, Volume: 1269, Article number : 133739, Pages count : DOI: 10.1016/j.molstruc.2022.133739

Authors

Serykh Andrey ^1,2 , Tretyakov Evgeny ¹ , Fedyushin Pavel ¹ , Ugrak Bogdan ¹ , Dutova Tatyana ¹ , Lalov Andrey ¹ , Korlyukov Alexander ³ , Akyeva Anna ¹ , Syroeshkin Mikhail ¹ , Bogomyakov Artem ⁴ , Romanenko Galina ⁴ , Artiukhova Natalia ⁴ , Egorov Mikhail ¹ , Ovcharenko Victor ^4,1

Affiliations

1	N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Ave. 47, Moscow 119991, Russia
2	D. Mendeleev University of Chemical Technology of Russia, Miusskaya Pl., 9, Moscow 125047, Russia
3	A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilova Str. 28, Moscow 119991, Russia
4	International Tomography Center, Siberian Branch of Russian Academy of Sciences, Institutskaya Str. 3a, Novosibirsk 630090, Russia

The aim of the study was to prepare and investigate structure and properties of a new series of stable nitronyl nitroxides bearing N-fluoroalkylpyrazolyl substituents. According to cyclic voltammetry data, a paramagnet with a difluoromethyl substituent can reversibly undergo electrochemical oxidation and reduction. In contrast, radicals with fluorinated ethyl substituents are electrochemically oxidized reversibly, but their electrochemical reduction is quasi-reversible. Molecular and crystal structures of the nitroxides were confirmed by single-crystal X-ray diffraction analysis. The crystal structures of the radicals were studied quantitatively in terms of pairwise interaction energies and energy framework analysis. Analysis of the energies of molecular pairs revealed that in crystalline phases of all nitroxides, the binding is the strongest in dimers assembled via C–H…O interactions of nitroxide O atoms with pyrazole and/or alkyl H atoms. Other dimers are formed predominantly by C–H…π interactions, and in some cases, their binding energy is almost equal to that for the aforementioned ones. The above contacts are complemented short contacts C–H…A and others, which predetermine the final crystal packing of radicals. A consequence of their packing is the geometry of relative arrangement of nitroxide groups and, above all, distances O…O between the oxygen atoms of the paramagnetic centers. These distances were found to exceed the sum of van der Waals radii; consequently, in solid phases of the paramagnets, weak antiferromagnetic exchange interactions are predominant (|J/kB| ≤ 2.74 K, H = –2J·S1S2.

Serykh A. , Tretyakov E. , Fedyushin P. , Ugrak B. , Dutova T. , Lalov A. , Korlyukov A. , Akyeva A. , Syroeshkin M. , Bogomyakov A. , Romanenko G. , Artiukhova N. , Egorov M. , Ovcharenko V.
N-Fluoroalkylpyrazolyl-substituted Nitronyl Nitroxides
Journal of Molecular Structure. 2022. V.1269. 133739 . DOI: 10.1016/j.molstruc.2022.133739 WOS Scopus OpenAlex

Web of science:	WOS:000878184600010
Scopus:	2-s2.0-85135127088
OpenAlex:	W4285678522

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